Abstract Introduction Mixta calida is a newly discovered gram-negative bacterium and represents an uncommon source of infection in adult with few documented cases. We report the only documented case of Mixta calida and Stenotrophomonas maltophilia coinfection associated with a central venous catheter infection. Case Presentation A 46-year-old male with chronic thromboembolic pulmonary hypertension was admitted for inpatient transition of pulmonary hypertension medications. His Hickman central venous catheter (CVC) was accessed to administer IV medications. Shortly thereafter, he became acutely hypoxic and tachycardic and a rapid response was called. Immediate evaluation revealed an SpO2 in the 70s, temperature of 100.8, BP 160/86 and heart rate in the 120’s. Physical examination was notable for central and peripheral cyanosis as well as significant, whole-body rigors. Labs were significant for lactate 5.5 and venous blood gas with pH 7.16/ pCO2 62. Chest x-ray demonstrated mild interstitial edema but otherwise no suspicious focal opacities or consolidations. His symptoms resolved after approximately 30 minutes and his lactate improved to 1.5 and venous blood gas showed pH 7.39/pCO2 34. The patient then reported that he had been recently experiencing similar symptoms with lesser severity also associated with accessing his CVC at home. Peripheral blood cultures were drawn which grew Mixta calida in 3 of 4 bottles and Stenotrophomonas maltophilia in 1 of 4 bottles after which the CVC was removed. Infectious disease was consulted, and the patient was started on IV piperacillin-tazobactam and oral trimethoprim-sulfamethoxazole (TMP-SMX) before susceptibilities resulted. He was de-escalated to TMP-SMX oral therapy for a total of 10 days. Discussion Mixta calida (previously Pantoea calida) is a gram-negative bacterium of the Enterobacterales order first discovered in 2010 and typically found as an environmental pathogen. Known cases of adult infection are rare. We found only one other documented case of Mixta calida and Stenotrophomonas maltophilia coinfection which was associated with a cardiac implantable electronic defibrillator wound infection. To our knowledge, this represents the first reported coinfection of Mixta calida and Stenotrophomonas maltophilia presenting as a central line-associated bloodstream infection (CLABSI). As an uncommon bacterium, Mixta calida may require advanced laboratory testing for detection. In our case, it required matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry to be identified. Fever and rigors are known to be associated with gram negative bacteremia but the transient nature of the symptoms in this case directly associated with accessing the CVC highlight an atypical presentation of infection with rare pathogens. This abstract is funded by: None
Luo et al. (Fri,) studied this question.